Pocket valve for valved bags made of plastics material sheeting and having crossed end closures

ABSTRACT

The pocket valve for a bag consists of a tube of plastics material sheeting, which tube is open in a portion of its length at its inner end along the two side edges. The lower of the two resulting flaps is backfolded and adhered to the corner tuck of the valve corner of the bag.

United States Patent Muller et al. [4 1 Aug. 1, 1972 [54] POCKET VALVE FOR VALVED BAGS [56] References Cited MADE OF PLASTICS MATERIAL SHEETING AND HAVING CROSSED UN'TED STATES PATENTS END CLOSURES 7 3,000,551 9/ i961 Atwood ..229/62.5 [72] Inventors: Reiner Muller, Wieda; Fritz Achel- FOREIGN PATENTS OR APPLICATIONS pohl, Lengerich, both of Germany I B [73] Assignee: Windmoller 8: Holscher, Lengerich I Essi mam of Westphalia, Germany [22] Filed: April 3, 1970 Primary Examiner Donald F. Norton [21] APP] No; 25,538 Attorney-Fleit, Glpple & Jacobson v 51 ABSTRACT f Application pnomy Dam The pocket valve for a bag consists of a tube of April 1969 19 17 480-2 plastics material sheeting, which tube is open in a por- 7, 1969 Germany 19 210-9 tion of its length at its inner end along the two side edges. The lower of the two resulting flaps is U-sthe [51] Int. Cl. ..Bd 31/14 valve comer f the bag 5 8] Field of Search ..229/62.5; /9

5 Claims, 14 Drawing Figures PATENTED B 1 I972 SHEET 1 [IF 3 INVENTORS Reiner MULLER FritzACHELPOHL t r ATTORNEYS PATENTEUAUE 1 I972 3.680.770

suwanrs INVENTORS Reiner MULLER Fritz ACHELPOHL hir/XTTORNFYS PATENTEHAUB 1 I972 3.680.770 sum 3 or 3 FlG.11b

INVENTORS Reiner MULLER Fritz ACHELPOHL t, ATTORNEYS room vitvaroavatvspaicsmusor PLASTICS mrssm. srmrmuc AND ruvmc cnossaossnctosuaas The present application relates to pocket valves for valved bags having crossed end closures, and a process and apparatus for the manufacture thereof.

For instance, the U.S. Pat. No. 3,581,978 of the assignees of the inventor(s) discloses a valved bag which consists of plastics material sheeting and is provided with crossed end closures, which are closed by adhered seams and one of contains in one cornerof the closure an adhered tubular valve insert, which has a free end that protrudes into the interior of the bag.

It is an object of the invention to provide for such bags having crossed end closures a so-called pocket valve and a process and apparatus for the manufacture thereof so that the advantages of said pocket valves which are known frompaper bags can be utilized also in valved bags consisting of plastics material sheeting and having crossed end closures.

The known pocket valve of paper cannot simply be made of plastics material and used in bags of plastics material because the thin plastics material sheeting to be used for a valve insertcannot be processed like paper and the known paper embodiments and the processes of manufacturing the same cannot be included in the process of manufacturing a valved bag made of plastics material, bearing in mind that the valved bag of plastics material is provided with adhered seams by means of a contact adhesive, which is applied and dried before the crossed end closure is folded.

This object is accomplished in accordance with the invention essentially in that the pocket valve is formed by ,an extruded seamless tube of plastics material, the inner end portion of said tube is open along the two side folds, and the lower of the two resulting flaps is backfolded and adhered to the corner tuck. Hence, the backfolded flap and the lower wall of the valve tube form a pocket, in which that end of the valve tube which protrudes from the bag can be inserted when the bag has been filled. This results in an excellent seal afforded by the valve.

A preferred process of manufacturing that pocket valve insert is characterized in that the still integral valve tubing is provided with laterally disposed, punched narrow apertures, which are spaced apart by distances equal to the length of the valve tube section and have the same length as the flaps to be formed, the valve tubing is then cut into sections by transverse perforation lines, which join the leading ends of each pair of punched apertures, each valve section is infolded on a fold line which joins the trailing ends of each pair of apertures, this infolding is effected by an operation in which the tube section is gripped, accelerated and torn from the tubing, whereby the upper flap immediately preceding the fold line is raised at the same time, said upper flap is backfolded by stationary means against the direction of travel, whereas the lower flap is retained, e.g., by a vacuum, and the resulting valve insert is introduced into the open crossed end closure.

It has been found that in adhered joints for which a relatively low bond strength is required the contact adhesive which is known from the French Pat. No. 1,395,952 issued on Mar. 8, 1965 of the assignees of the present inventor(s) will even be effective if it is ap- 2 plied only to one surface, provided that the other surface of plastics material has been subjected to a sur face-activating pretreatment. Particularly if the undesired intermittent application of the contact adhesive to the valve insert is to be avoided, the above-mentioned embodiment of the pocket valve requires a pretreatment of the valve tube material on its inside because the backfolded flap is adhesively joined on the previous inside of the tube to the corner tuck. An internal pretreatment of extruded seamless tubing involves special requirements and can be carried out only with expensive means. For this reason it is another object of the invention to propose a second embodiment of a pocket valve which can be made without need for an internal pretreatment of a seamless extruded tubing.

This additional object of the invention is accomplished in that the pocket valve insert consists of a sheet of plastics material sheeting, which sheet has been folded on itself and has superimposed edges,

which are joined by a seam weld, which is omitted in a length which corresponds to the length of the flap to be backfolded, whereas the fold is open on the opposite side in a corresponding length.

Such pocket valve may be made from an open web, which can easily be subjected to a surface-activating pretreatment on the side where this is desired. The open valve sheeting web is fed integrally and is provided at the center with punched apertures or simple longitudinal slits, which are spaced apart by distances corresponding to the length of the valve tube sections and which have the same length as the flaps. The web is folded on itself symmetrically to the punched apertures to form a half tubing, which is then closed by a longitudinal seam weld to form a tubing. The seam weld is interrupted in length portions which are in register with the punched apertures so that the above-mentioned flaps are formed. Transverse perforation lines are then formed, by which the punched apertures or the portions where the seam welds are interrupted are crossed at their leading ends. The manufacture is then continued in the manner which has been described for the valve material web, a punching or slitting device, op-

tionally a longitudinal folding device and an intermittently operating longitudinal welding device, devices for forming transverse perforation lines in the a preformed valve material web, and finally a folding and flap-backfolding device, the latter being characterized according to the invention in that vacuum nozzles for retaining the lower flap precede a folding gripper, which is arranged in known manner in a rotating cylinder, and a stationary backfolding device is provided in the path of the upper flap which has been raised by the folding operation. The cylinder provided with the folding gripper cooperates with a rotating folding knife and serves also for tearing off the foremost valve section and for inserting the preformed pocket valve insert into the crossed end closure of a blank for a valved bag having a crossed end closure, which crossed end closure is moved past the folding cylinder tangentially thereto.

The invention will now be described more fully with reference to embodiments shown by way of example in the drawings, in which FIG. 1 shows a valved bag having still open crossed end closures and an inserted pocket valve,

FIG. 2 is a sectional view taken on line 11-" in FIG. 1,

FIG. 3 is an enlarged top plan view showing a first embodiment of the pocket valve,

FIG. 4 is a side elevation of FIG. 3,

FIG. 5 is an enlarged top plan view showing a second embodiment,

FIG. 6 is aside elevation of FIG. 5,

FIG. 7 is a top plan view showing pocket valves of FIGS. 3 and 4 during the. manufacture thereof,

FIG. 8 is an elevation taken in the direction of arrow A in FIG. 7.

FIGS. 9a and 9b are top plan views showing pocket valves of FIGS. 5 and 6, respectively, during their manufacture,

FIG. 10 is a diagrammatic side elevation of the device for folding the pocket valve, backfolding the lug and inserting the pocket valve.

FIGS. 1 la and 1 lb are top plan views showing sheeting webs for making the pocket valves of FIGS. 5 and 6, respectively, in a modified process.

FIG. 12 is a sectional view taken on line XII-XII in FIG. 1 la.

The pocket valve 1 according to the invention consists of a tube section 2, which consists of plastics material sheeting and which on its sides is open in part of its length at one end so that two flaps 3 and 4 are formed, one of which, 4, is backfolded. This backfolded flap 4 of the pocket valve insert is adhered to the corner tuck 5 of one of the two open crossed end closures 6 and 7 of a blank 8 for a valved bag having crossed end closures, asis indicated by the hatching 9.

The end closures are closed and sealed by folding the side flaps over along the two parallel dot-dash lines of each end closure 6 and 7, whereupon the side flaps of end closure 6 overlie the valve tube 2. When the bag has been filled through the valve tube, the end of the tube facing outwardly can be backfolded and stuck into pocket 10 which i'sformed by the backfolded flap 4 and the adjacent portion of valve tube 2. In this way, the valve is reliably protected against any ingress of fluids, dust or rain, etc. from the outside.

The width of the tube exceeds the width of the end closure in its closed condition and the tube has protruding side edges that are adapted to be folded over together with the side flaps of the end closure. The fact that the width of the valve tube exceeds the width of the end closure in its closed condition appears from FIG. 1 of the drawings, whereinthe two parallel lines in the open end closure indicate the lines along which the side flaps are folded over. The distance between each two parallel fold-lines therefore is the width of the closed end closure. It will also become clear that the side edges of the valve tube projecting beyond the fold lines are folded over together with the side flaps when closing the end closure.

A first embodiment of such pocket valve (FIGS. 3 and 4) consists of an extruded seamless tube section I 1 of plastics material sheeting. The side edges of said tube section have been removed in narrow areas 14 and 15 so that flaps l2 and 13 are defined. For the same purpose, the side edges may simply be slit. The flap I3 is backfolded to form the pocket 16 and to secure the pocket valve insert to the corner tuck.

A second embodiment (FIGS. 5 and 6) of a pocket valve according to the invention consists of a sheet 17, 18, which is made from plastics material sheeting and has been folded on itself. Superimposed edges 19, 20 of said sheet are joined by a seam weld 21, except for the portion 24, which defines the flaps 22, 23. Material has been removed in a narrow area 26 on the side of the fold line 25, or the fold line is slit to expose the flaps '22, 23 also on this side so that the flap 23 .can be backfolded.

Although the longitudinal seam weld 21 is subjected to an undesired stress tending to peel it open, that seam weld will not improperly weaken the valve because such valve tube inserts are preferably wider than the crossed end closure so that the edges of the insert are backfolded together with the backfolded portions of the end closure and the longitudinal seam lying in the backfolded portion is relieved from stress. This em- 20 bodiment having backfolded valve tube edges affords the advantage that the width of the valve tube is not critical.

Pocket valves made in accordance with FIGS. 3 and 4 are made in the manner shown in FIGS. 7 and 8 from an endless extruded seamless tubing 27. The latter is provided with laterally disposed, punched apertures 14 and 15, which are spaced suitable distances apart, and is subsequently provided with transverse perforation lines 28, which join the leading ends of said apertures. The leading workpiece 29 is-torn off along said transverse perforation lines and, e.g., the upper flap I3 is backfolded rearwardly to the position 13' shown in dash-dot lines. The resulting backfolded flap 13' of the pocket valve insert is subsequently adhered to the comer tuck of an open crossed end closure, which is subsequently sealed.

Pocket valves shown in FIGS. 5 and 6 are made from an endless web 30 of plastics material sheeting. This web is first provided along its center line 31, e.g., with slits 32, which are spaced the desired distances apart. The web 30 is then folded about its center line 31 to form a half tubing 33. The superimposed edges of the web are joined by an intermittent longitudinal seam weld 21, which alternates with non-welded sections 24 t in register with the slits 32. Transverse perforation lines 34 are then provided, which join the leading ends of the slits and the non-welded sections and along which the leading workpiece 35 is torn 0E. The upper flap, 23 is device is succeeded by a device for forming a weakened transverse zone, and a feeding device 36, 37 (FIG. 10), which is succeeded by a cylinder 38 pro vided according to the invention and serving for tearing off, folding, flap backfolding, and valve insert inserting. The cylinder 38 is provided with a folding gripper 39, 40, which cooperates with a rotating folding knife 41.

The cylinder is provided with vacuum nozzles 42, and a stationary backfolding tool 44 is provided near the cylinder outside the flight circle 43 of the folding knife 41. The nozzles 42 and the tool 44 immediately precede the movable jaw 40 of the folding gripper. The cylinder 38 is provided in known manner with the path of travel 45 of the blanks for making valved bags, which are advanced in a transverse orientation and have open crossed end closures.

When the pocket valve tubing 27 or 33 has been prepared to the state in which it has been provided with the weakened transverse lines 28 or 34, the tubing is supplied by the feeding elements 36, 37 to the cylinder 38, which is adjusted so that the leading workpiece 29 or 35 is gripped on the fold line 24 for the flap 13 or 23, which is to be backfolded. The lower flap 12 or 22 is retained on the cylinder by the vacuum nozzles 42. As a result of the folding, the upper flap 13 or 23 is raised and during the continued movement of the cylinder 38 strikes the backfolding rod 44, by which it is backfolded rearwardly, opposite to the direction of travel. Because the cylinder 38 has a peripheral velocity which is equal to the velocity of the bag blanks travelling in the plane 45, and the length in which the tubing is to be fed by the feeding elements 36, 37 for each bag blank corresponds only to the length of the pocket valve insert, the peripheral speed of the cylinder 38 is much higher than the feeding speed of the valve tubing so that the leading blank which has been gripped by the folding device 31-41 is torn at the leading weakened transverse line 28 or 34. The finished pocket valve insert 1 (FIG; is shown in dash-dot lines and has a backfolded upper flap 13 or 23 or 4. As the rotation of the cylinder 38 is continued, the finished pocket valve insert 1 is fed to a trailing corner of an open crossed end closure of a blank for a valved bag having crossed end closures and is adhered to the corner tuck 5 by means of the adhesive 9 applied thereto.

Particularly when the pocket valves are made from very thin sheeting, it may prove undesirable in the process described with reference to FIG. 9 to form apertures or slits before the half tubing has been made from the web of plastics material sheeting. Because the half tubing is formed from the web by a folding triangle and the apertures or slits are disposed at the apex of said triangle, said apex may enter the apertures or slits and may tear open the web along the center line 31.

In the process which has been explained with reference to FIG. 11, that danger may be eliminated in that the plastics material sheeting web 30 is initially folded on itself to form a half tubing 33 and is then provided with the aid of a cutting device 46 in the longitudinal fold line 47 with slits or apertures 32 having a length which corresponds to the pocket valve lengths.

' The superimposed edges of the web 30 of plastics material sheeting are then joined by the intermittent longitudinal seam weld 21, which is interrupted by nonwelded portions 24 in register with the slits 32. The remaining process steps and the further processing of the pocket valves are performed in the manner which has been described with reference to FIGS. 9 and 10. A blank for such pocket valve is shown in FIG. 11b. Because in theprocess illustrated in FIG. 11 the cutting device 46 succeeds the longitudinal folding device, the

' slits 32 no longer collide with the apex of the folding triangle butare reliably cut into the longitudinal fold line 47 of the pocket valve to be formed.

The cutting device 46 consists of an oscillating knife 48, which is pivoted on an axle 49 and by drive means, not shown, is moved with corresponding intervals of time in the direction of the double arrow 50. A guide plate 51 is disposed between the plies of the web 30 of plastics material sheeting which has been folded on itsiderable expenditure. As the corresponding side of the flat sheeting web 30 can easily be pretreated, the embodiment shown in FIGS. 5, 6 and 9, 11 will be preferred in practice. a

When it is desired or required for a very strong adhered joint, the backfolded flaps 13, 23 may be provided with an adhesive coating during the movement of the pocket valves, held by the folding gripper 39, 40, from the folding station tothe station in which they are inserted at the path of travel 45. This adhesive may be applied'by means of an adhesive applicator, which is disposed in register with the cylinder 38 and provided with printing blocks which are dimensioned to match the flaps.

The invention is unique in enabling the use of a pocket valve, having advantages known from paper bags, in bags made from plastics material sheeting and having crossed end closures. The pocket valve according to the invention has such a form that it can be made from plastics material sheeting although the same can be processed only with difficulty. The manufacturing processes provided according to the invention are simple and can be carried out reliably in continuous operation. In view of the large number of steps performed by the apparatus provided according to the invention and serving for folding, tearing, flap-backfolding and valveinserting operations, said apparatus is surprisingly simple, efficient, reliable in operation and compact.

What is claimed is:

1. A pocket type valve in combination with a bag having folded end closures comprising two opposing corner flaps and two opposing side flaps, said valve comprising a flattened tube of plastic material sheeting having two opposing side edges said tube being open in a portion of its length at one end thereof along said two .side edges to form two superposed flaps, the lower one of said flaps being backfolded and adhered to one of said corner flaps of the bag such that the other end of said tube faces outwardly, and said side flaps being adapted to be folded over for closing said end closure so as to overlie said tube.

2. A pocket type valve according to claim 1, wherein 'the'width of said tube exceeds the width of said end closure in its closed condition and said tube having protruding side edges adapted to be folded over together with said side flaps of said end closure.

seam weld except for a length portion, and the fold is slit in a length portion which is in register with the firstmentioned length portion.

5. A pocket valve according to claim 1, characterized in that the backfolded flap has been subjected to a surface-activating pretreatment on its side which faces the corner tuck and is adhered thereto. 

1. A pocket type valve in combination with a bag having folded end closures comprising two opposing corner flaps and two opposing side flaps, said valve comprising a flattened tube of plastic material sheeting having two opposing side edges said tube being open in a portion of its length at one end thereof along said two side edges to form two superposed flaps, the lower one of said flaps being backfolded and adhered to one of said corner flaps of the bag such that the other end of said tube faces outwardly, and said side flaps being adapted to be folded over for closing said end closure so as to overlie said tube.
 2. A pocket type valve according to claim 1, wherein the width of said tube exceeds the width of said end closure in its closed condition and said tube having protruding side edges adapted to be folded over together with said side flaps of said end closure.
 3. A pocket valve according to claim 1, characterized in that the pocket valve consists of an extruded seamless tube of plastics material sheeting and each side edge of said tube is removed in a narrow area defining the flaps.
 4. A pocket valve according to claim 1, characterized in that the pocket valve consists of a sheet of plastics material sheeting, which sheet is folded on itself and has superimposed edges, which are joined by a seam weld except for a length portion, and the fold is slit in a length portion which is in register with the first-mentioned length portion.
 5. A pocket valve according to claim 1, characterized in that the backfolded flap has been subjected to a surface-activating pretreatment on its side which faces the corner tuck and is adhered thereto. 